In the mashing process in brewing, malt is converted by mixing the malt with water and heating the mash to elevated temperatures to solubilize and saccharify the starches. In traditional brewing practice, a malt-to-water weight ratio of about 0.30 to 1 is used in the mash, and the malt is added to the water at a temperature in the range of 100.degree. F. and 146.degree. F. and held at this temperature for a period of about 20 to 40 minutes. This serves to wet down the malt and liquify the starch. The mash is then heated to a conversion temperature and held at this temperature for a period of up to 60 minutes. The conversion temperature provides the proper environment for optimum enzyme activity for conversion of the liquified starch.
After completion of conversion or saccharification, the mash is raised to a "mash-off" temperature and is held at this temperature for a short period to terminate the enzyme activity.
In the conventional brewing practice, the mash is then pumped to the lauter tub where the spent grains are separated from the liquid portion of the mash to provide a wort which is subsequently delivered to the brew kettle. In the lauter tub the grains settle to the bottom of the tub to form a bed which acts as a filtering medium. In the typical lautering procedure, the wort initially discharged from the lauter tub is recycled back to the lauter tub and the recycling is continued until a clear wort is obtained, which is then sent to the brew kettle.
After the wort has been withdrawn to a level just covering the grain bed, sparge water is sprayed into the bed to maintain a constant head in the lauter tub and a constant run-off to the brew kettle. The sparging is continued until a desired liquid level is attained in the brew kettle.